Hello everyone,
I am using CESM1.2 with the CAM4 component for a paleoclimate simulation with an ancient topography. I have set up globally uniform aerosol forcing by modifying the input files for prescribed aerosols (prescribed_aero_file) and aerosol deposition fluxes (aerodep_flx_file) to be homogeneous, without any spatial variation. The goal is to have aerosol concentrations at 1500 times the modern global mean.
However, the output shows inconsistencies: the AEROD_v (total aerosol optical depth in the visible band) and surface solar radiation fluxes (FSDS and FSDSC) still reflect patterns influenced by modern topography. For example, in regions where the ancient topography is ocean but the modern topography is land, FSDS values are unusually low, and AEROD_v is abnormally high. The land fraction output (landfrac) correctly matches the ancient topography, indicating that the base topography is applied properly.
I have already verified that the input aerosol files are globally uniform. Could you please advise which files or processes in CAM4 might be causing this issue? What steps should I take to ensure that AEROD_v and FSDS also become globally uniform, matching the homogeneous aerosol inputs?
Thank you for your assistance.
I am using CESM1.2 with the CAM4 component for a paleoclimate simulation with an ancient topography. I have set up globally uniform aerosol forcing by modifying the input files for prescribed aerosols (prescribed_aero_file) and aerosol deposition fluxes (aerodep_flx_file) to be homogeneous, without any spatial variation. The goal is to have aerosol concentrations at 1500 times the modern global mean.
However, the output shows inconsistencies: the AEROD_v (total aerosol optical depth in the visible band) and surface solar radiation fluxes (FSDS and FSDSC) still reflect patterns influenced by modern topography. For example, in regions where the ancient topography is ocean but the modern topography is land, FSDS values are unusually low, and AEROD_v is abnormally high. The land fraction output (landfrac) correctly matches the ancient topography, indicating that the base topography is applied properly.
I have already verified that the input aerosol files are globally uniform. Could you please advise which files or processes in CAM4 might be causing this issue? What steps should I take to ensure that AEROD_v and FSDS also become globally uniform, matching the homogeneous aerosol inputs?
Thank you for your assistance.